The changing face of Parkinson's disease-associated psychosis: a cross-sectional study based on the new NINDS-NIMH criteria.

International audienceNew criteria for Parkinson's disease-associated psychosis (PDAP) were recently proposed by a NINDS-NIMH working group. We assessed 116 consecutive unselected outpatients with PD for the existence of psychotic symptoms during the previous month, using a structured questionnaire covering the whole spectrum of PDAP symptoms. Hallucinations occurred in 42% of the patients (visual: 16%; nonvisual: 35%), delusions in 4%, and minor symptoms in 45% (sense of presence, visual illusions, or passage hallucinations). The prevalence of PDAP was 43% when the usual definition was used (hallucinations and/or delusions) and 60% when the NINDS-NIHM criteria were used. Correlations between PDAP and patient characteristics varied with the definition of PDAP. These findings suggest that the epidemiology of PDAP should be re-evaluated with the new criteria. Minor symptoms and nonvisual hallucinations are an important part of the PDAP spectrum, which has commonly been restricted to visual hallucinations and delusions

Behavioral and Neural Correlates of Communication via Pointing

Communicative pointing is a human specific gesture which allows sharing information about a visual item with another person. It sets up a three-way relationship between a subject who points, an addressee and an object. Yet psychophysical and neuroimaging studies have focused on non-communicative pointing, which implies a two-way relationship between a subject and an object without the involvement of an addressee, and makes such gesture comparable to touching or grasping. Thus, experimental data on the communicating function of pointing remain scarce. Here, we examine whether the communicative value of pointing modifies both its behavioral and neural correlates by comparing pointing with or without communication. We found that when healthy participants pointed repeatedly at the same object, the communicative interaction with an addressee induced a spatial reshaping of both the pointing trajectories and the endpoint variability. Our finding supports the hypothesis that a change in reference frame occurs when pointing conveys a communicative intention. In addition, measurement of regional cerebral blood flow using H2O15 PET-scan showed that pointing when communicating with an addressee activated the right posterior superior temporal sulcus and the right medial prefrontal cortex, in contrast to pointing without communication. Such a right hemisphere network suggests that the communicative value of pointing is related to processes involved in taking another person's perspective. This study brings to light the need for future studies on communicative pointing and its neural correlates by unraveling the three-way relationship between subject, object and an addressee

Viewing another person's body as a target object: a behavioural and PET study of pointing.: Pointing at a person's body

International audienceHumans usually point at objects to communicate with other persons, although they generally avoid pointing at the other's body. Moreover, patients with heterotopagnosia after left parietal damage cannot point at another person's body parts, although they can point at objects and at their own body parts and although they can grasp the others' body parts. Strikingly, their performance gradually improves for figurative human body targets. Altogether, this suggests that the body of another real person holds a specific status in communicative pointing. Here, we test in healthy individuals whether performance for communicative pointing is influenced by the communicative capacity of the target. In Experiment 1, pointing at another real person's body parts was compared to pointing at objects, and in Experiment 2, the person was replaced by a manikin. While reaction times for pointing at objects were shorter compared to pointing at other person's body parts, they were similar for objects and manikin body parts. By adapting Experiment 1 to PET-scan imaging (Experiment 3), we showed that, compared to pointing at objects, the brain network for pointing at other person's body parts involves the left posterior intraparietal sulcus, lesion of which could cause heterotopagnosia. Taken together, our results indicate that the specificity of pointing at another person's body goes beyond the visuo-spatial features of the human body and might rather rely on its communicative capacity

Pointing and the notion of second person : study in healthy and brain-lesioned adults

La désignation est le geste de montrer un objet à une autre personne. La structure de la désignation est similaire à celle du discours verbal : la première personne « je » communique avec la seconde personne « tu » à propos de l'objet « il ». A partir de la description neuropsychologique d'un trouble acquis de la désignation, l'hétérotopagnosie ou incapacité à désigner le corps d'autrui, nous jetons les bases d'un nouveau modèle de la désignation impliquant la notion de seconde personne « tu ». Nous proposons et validons l'hypothèse que toute désignation implique de se représenter le point de vue de l'interlocuteur « tu » grâce à un référentiel hétérocentré. De plus, chez les patients hétérotopagnosiques comme chez les volontaires sains, désigner le corps d'autrui est plus difficile que désigner les objets. Nous expliquons ce phénomène par le fait que seul le corps humain vivant peut être à la fois sujet de communication et objet de communication. Poursuivant notre investigation sur la notion de seconde personne, nous montrons chez une patiente et chez les sujets sains que le corps des femmes est également plus difficile à désigner que celui des hommes. Les femmes seraient plus facilement considérées comme des sujets que les hommes. Enfin, nous avons recherché comment l'humain percevait la désignation réalisée par autrui comme témoignant d'une intention de communication à propos d'un objet. L'engagement dans une relation avec la seconde personne « tu » est nécessaire à cette compréhension. Au total, cette thèse apporte les premiers éléments expérimentaux sur les mécanismes de la relation de communication avec la seconde personne « tu ».Pointing is used to communicate about an object with another person. This skill has a triadic structure similar to speech: the first person “I” communicate with the second person “you” about an object of interest “it”. From the neuropsychological description of an acquired deficit in pointing, heterotopagnosia which is the inability to point at another person's body parts, we build a new cognitive model involving the notion of a second person to explain pointing behaviour. We bring experimental evidence that pointing requires taking the addressee's perspective through the elaboration of a heterocentric reference frame. Furthermore, we show that in heterotopagnosic patients and in healthy subjects pointing at another person's body is more difficult than pointing at objects. We hypothesize that it is because only the living human body of other can be a subject to communicate with and an object to communicate about. In addition, we show that heterotopagnosic patients and healthy subjects find it more difficult to point at female body parts than at male ones, perhaps because women are more easily considered as subjects. Finally, we explore the behavioural and neural bases of the perception of pointing. We confirm that the relationship with the second person is necessary to understand the communicative intention of the addressee about the object. As a whole, this work provides the first cognitive and neural evidence for the notion of a second person in the brain

La désignation et la notion de seconde personne : étude chez l'adulte sain et cérébro-lésé

Pointing is used to communicate about an object with another person. This skill has a triadic structure similar to speech: the first person “I” communicate with the second person “you” about an object of interest “it”. From the neuropsychological description of an acquired deficit in pointing, heterotopagnosia which is the inability to point at another person's body parts, we build a new cognitive model involving the notion of a second person to explain pointing behaviour. We bring experimental evidence that pointing requires taking the addressee's perspective through the elaboration of a heterocentric reference frame. Furthermore, we show that in heterotopagnosic patients and in healthy subjects pointing at another person's body is more difficult than pointing at objects. We hypothesize that it is because only the living human body of other can be a subject to communicate with and an object to communicate about. In addition, we show that heterotopagnosic patients and healthy subjects find it more difficult to point at female body parts than at male ones, perhaps because women are more easily considered as subjects. Finally, we explore the behavioural and neural bases of the perception of pointing. We confirm that the relationship with the second person is necessary to understand the communicative intention of the addressee about the object. As a whole, this work provides the first cognitive and neural evidence for the notion of a second person in the brain.La désignation est le geste de montrer un objet à une autre personne. La structure de la désignation est similaire à celle du discours verbal : la première personne « je » communique avec la seconde personne « tu » à propos de l'objet « il ». A partir de la description neuropsychologique d'un trouble acquis de la désignation, l'hétérotopagnosie ou incapacité à désigner le corps d'autrui, nous jetons les bases d'un nouveau modèle de la désignation impliquant la notion de seconde personne « tu ». Nous proposons et validons l'hypothèse que toute désignation implique de se représenter le point de vue de l'interlocuteur « tu » grâce à un référentiel hétérocentré. De plus, chez les patients hétérotopagnosiques comme chez les volontaires sains, désigner le corps d'autrui est plus difficile que désigner les objets. Nous expliquons ce phénomène par le fait que seul le corps humain vivant peut être à la fois sujet de communication et objet de communication. Poursuivant notre investigation sur la notion de seconde personne, nous montrons chez une patiente et chez les sujets sains que le corps des femmes est également plus difficile à désigner que celui des hommes. Les femmes seraient plus facilement considérées comme des sujets que les hommes. Enfin, nous avons recherché comment l'humain percevait la désignation réalisée par autrui comme témoignant d'une intention de communication à propos d'un objet. L'engagement dans une relation avec la seconde personne « tu » est nécessaire à cette compréhension. Au total, cette thèse apporte les premiers éléments expérimentaux sur les mécanismes de la relation de communication avec la seconde personne « tu »

Etude neuropsychologique, psychophysique et anatomo-fonctionnelle de la désignation proto-déclarative (vers un modèle cognitif des relations de communications triadiques)

Par l'étude de la désignation proto-déclarative, nous avons recherché les représentations cérébrales nécessaires aux interactions triadiques. L'acquisition de ce comportement marque un stade crucial dans le développement de l'enfant, puisque son absence révèle souvent un autisme. Des lésions sont responsables de troubles acquis de la désignation : certaines représentations cérébrales nécessaires à la désignation peuvent donc être spécifiquement lésées. Suite à l'étude neuropsychologique des déficits présentés par un patient, nous avons postulé l'existence d'une représentation dédiée à la reconnaissance du corps d'autrui et à reconsidérer son importance dans toute désignation. Les résultats de trois études psychophysiques chez le sujet sain nous permettent d'impliquer dans la désignation une représentation du corps humain d'autrui capable de communication et une représentation spatiale du point de vue d'autrui. Enfin, des activations cérébrales en PETscan révèlent les aires cérébrales nécessaires à ces représentations. Nous proposons finalement un modèle de la désignation afin de rendre compte des déficits retrouvés chez les patients.Studying proto-declarative pointing we have searched cerebral representations necessary for triadic interactions. The acquisitions of this skill marks a critical step in child development, since its absence usually reveals autism. Acquired troubles of proto-declarative pointing have been associated with focal cerebral lesions, there must be cerebral representations necessary for proto-declarative pointing that can be specifically damaged. One patient's performances made us postulate the existence of a cerebral representation dedicated to other's body recognition, and forced us to consider again its importance in proto-declarative pointing. According to the results from three psychopysics studies in healthy subjects, at least two types of representations may be implied in proto-declarative pointing : an other's human body representation and a spatial representation of other's perspective. Activation PETstudy reveals cerebral areas underlying these representations. Finally, we propose a new cognitive model of proto-declarative pointing to integrate these results and to explain the patients'deficits.PARIS12-Bib. électronique (940280011) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

La désignation et la notion de seconde personne (étude chez l'adulte sain et cérébro-lésé)

La désignation est le geste de montrer un objet à une autre personne. La structure de la désignation est similaire à celle du discours verbal : la première personne je communique avec la seconde personne tu à propos de l'objet il . A partir de la description neuropsychologique d'un trouble acquis de la désignation, l'hétérotopagnosie ou incapacité à désigner le corps d'autrui, nous jetons les bases d'un nouveau modèle de la désignation impliquant la notion de seconde personne tu . Nous proposons et validons l'hypothèse que toute désignation implique de se représenter le point de vue de l'interlocuteur tu grâce à un référentiel hétérocentré. De plus, chez les patients hétérotopagnosiques comme chez les volontaires sains, désigner le corps d'autrui est plus difficile que désigner les objets. Nous expliquons ce phénomène par le fait que seul le corps humain vivant peut être à la fois sujet de communication et objet de communication. Poursuivant notre investigation sur la notion de seconde personne, nous montrons chez une patiente et chez les sujets sains que le corps des femmes est également plus difficile à désigner que celui des hommes. Les femmes seraient plus facilement considérées comme des sujets que les hommes. Enfin, nous avons recherché comment l'humain percevait la désignation réalisée par autrui comme témoignant d'une intention de communication à propos d'un objet. L'engagement dans une relation avec la seconde personne tu est nécessaire à cette compréhension. Au total, cette thèse apporte les premiers éléments expérimentaux sur les mécanismes de la relation de communication avec la seconde personne tu .Pointing is used to communicate about an object with another person. This skill has a triadic structure similar to speech: the first person I communicate with the second person you about an object of interest it . From the neuropsychological description of an acquired deficit in pointing, heterotopagnosia which is the inability to point at another person's body parts, we build a new cognitive model involving the notion of a second person to explain pointing behaviour. We bring experimental evidence that pointing requires taking the addressee's perspective through the elaboration of a heterocentric reference frame. Furthermore, we show that in heterotopagnosic patients and in healthy subjects pointing at another person's body is more difficult than pointing at objects. We hypothesize that it is because only the living human body of other can be a subject to communicate with and an object to communicate about. In addition, we show that heterotopagnosic patients and healthy subjects find it more difficult to point at female body parts than at male ones, perhaps because women are more easily considered as subjects. Finally, we explore the behavioural and neural bases of the perception of pointing. We confirm that the relationship with the second person is necessary to understand the communicative intention of the addressee about the object. As a whole, this work provides the first cognitive and neural evidence for the notion of a second person in the brain.PARIS-EST-Université (770839901) / SudocSudocFranceF

The second person in “I”-“you”-“it” triadic interactions

International audienceSecond person social cognition cannot be restricted to dyadic interactions between two persons (the “I” and the “you”). Many instances of social communication are triadic, and involve a third person (the “him/her/it”), which is the object of the interaction. We discuss neuropsychological and brain imaging data showing that triadic interactions involve dedicated brain networks distinct from those of dyadic interactions

Approximating dementia prevalence in population-based surveys of aging worldwide: An unsupervised machine learning approach.

IntroductionAbility to determine dementia prevalence in low- and middle-income countries (LMIC) remains challenging because of frequent lack of data and large discrepancies in dementia case ascertainment.MethodsHigh likelihood of dementia was determined with hierarchical clustering after principal component analysis applied in 10 population surveys of aging: HRS (USA, 2014), SHARE (Europe and Israel, 2015), MHAS (Mexico, 2015), ELSI (Brazil, 2016), CHARLS (China, 2015), IFLS (Indonesia, 2014-2015), LASI (India, 2016), SAGE-Ghana (2007), SAGE-South Africa (2007), SAGE-Russia (2007-2010). We approximated dementia prevalence using weighting methods.ResultsEstimated numbers of dementia cases were: China, 40.2 million; India, 18.0 million; Russia, 5.2 million; Europe and Israel, 5.0 million; United States, 4.4 million; Brazil, 2.2 million; Mexico, 1.6 million; Indonesia, 1.3 million; South Africa, 1.0 million; Ghana, 319,000.DiscussionOur estimations were similar to prior ones in high-income countries but much higher in LMIC. Extrapolating these results globally, we suggest that almost 130 million people worldwide were living with dementia in 2015